You clearly have no idea what you're talking about. Canonical is building Mir to replace X so that it can be used in it's mobile devices. They are not putting effort into Wayland because it is licensed as MIT where Mir will be GPLv3. This is to safeguard Ubuntu mobile devices. XMir is required just as XWayland is required to bridge the transition gap. I'm not advocating Mir in any way but facts are facts.